$ { {-1} \times \left[\begin{array}{rrr}{4} & {0} & {-1} \\ {3} & {2} & {-1}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-1}\times{4} & {-1}\times{0} & {-1}\times{-1} \\ {-1}\times{3} & {-1}\times{2} & {-1}\times{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-4} & {0} & {1} \\ {-3} & {-2} & {1}\end{array}\right]}$